Fast Method for the Iron Losses Prediction in Inverter Fed Induction Motors

In this paper an easy method for the iron loss prediction in PWM inverter fed induction motors is presented. The method was initially proposed and validated for the prediction of the iron losses in non-oriented soft magnetic material with PWM supply. Starting from the iron losses measured with sinusoidal supply and the PWM waveform characteristics, a fast and reliable prediction of the iron losses in the motor can be obtained too. The method requires the separation of the iron losses in the hysteresis and eddy current components with sinusoidal supply, plus the average rectified and RMS values of the applied PWM voltage. The proposed method has been proved on an induction motor prototype able to provide a good accuracy in the iron losses measurement. The comparison between the measured and predicted iron losses with PWM supply have shown an excellent agreement with an error lower then the 5%, confirming the method validit

The impact of variable speed drives on energy efficient induction motors

Includes abstract.Includes bibliographical references.In an era when the world is faced with diminishing resources and energy security concerns, the slightest energy savings can prove essential in energy conservation. Induction motors and motorised loads consume an estimated 60% of the total energy required in the South African industry. This figure stands at 40% worldwide. Energy Efficient induction motors have proven to be an effective solution in the quest to reduce energy consumption. In South Africa, there have been efforts to replace the standard motors already in operation with energy efficient motors. The South African Utility, ESKOM, through its energy efficiency motor programme, has been providing incentives to its industrial customers to speed up this process

Investigations on the performances of the electrical generator of a rim-driven marine current turbine”

In this paper, the electrical generator of a rim-driven horizontal-axis current turbine is modeled in detail. Its main characteristics and performances are evaluated (efficiency, mass, cost, etc). This generator is of permanent magnet direct-driven synchronous type and is connected to a variable speed power electronics drive. It is then compared to a more traditional technology (a pod generator) in terms of mass and cost for a common set of specification. In addition, due to the specific geometry of the machine, the use of low-cost ferrite magnets is investigated in place of NdFeB magnets

The state-of-the-art of power electronics in Japan

Since the late 1950s, power electronics has been developing by leaps and bounds without saturation to become the key technology essential to modern society and human life as well as to electrical engineering. This paper mainly focuses on the state-of-the-art of power electronics technology and its medium to high-power applications because the author cannot survey the whole spectrum of power electronics ranging from a 5 W switching regulator to a 2.8 GW high-voltage DC transmission system now under construction in Japan. This paper also presents prospects and directions of power electronics in the 21st Century, including the personal views and expectations of the author</p

Iron losses in non-oriented steel subjected to matrix and DC-link converter supply : an experimental and analytical study on variable speed drives

A system approach to variable speed drives consisting of two low voltage induction motors (Y and A connection) fed by matrix and two-level DC-link converters is developed (chapter 7). The ratio of iron to copper winding losses is studied based on the induction motor equivalent circuit and constant V/f converter control. Electrical efficiency increased by up to 10% (partial load and low speed) in Y-connected motors fed by the matrix converter. While similar values of efficiency were observed in A-configured motors, up to 8% higher output power is extracted from the machines under two-level DC-link converter supply.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Medical Grade High Frequncy Power Distribution Units

The focus of this thesis is to design, model, build, and test a series resonance converter that uses a high frequency isolation transformer, offering significant reduction in size and cost, for powering a Computed Tomography (CT) scanner. The design increases the power quality for the load by isolating the grid side disturbances, and providing regulated desired voltage. The proposed architecture also allows for an optimized point of integration with an UPS, a regulated DC bus to improve waveform fidelity of x-ray generator, and active monitoring and control of the power architecture. Conventional CT systems use a 60Hz transformer, which not only occupies large footprints but also uses large amounts of copper and iron with increasing cost trajectory. In comparison to the traditional Power Distribution Units (PDU), the medical grade high frequency PDU presented in this thesis provides higher power quality and performance at a lower cost. The new CT systems possess unprecedented performance capability in terms of rotational speed and x-ray voltage modulation ( Ultra-Fast kV ) fidelity. In order to achieve such capabilities, a tightly regulated high power DC bus (700VDC, 150kW) is required. The system implemented in this thesis satisfies these new requirements. Design requirements, proposed architecture and controls, modeling, implementation and test results of the proposed system, including thermal analysis and electromagnetic compatibility, are presented in details in this thesis

Design and Control of a Multiphase Interleaving DC-DC Converter with Loss Optimizing Operating Strategies for Electric Vehicle

The drivetrain components of commercial electric vehicles include the battery pack, inverter, and electric machine. However, in such a drivetrain configuration, the inverter input voltage (DC-Link voltage) is equal to the battery voltage, which presents some drawbacks. Firstly, different values are required to achieve the optimum voltage level during the battery stack and electric machine design process. Secondly, the battery state of charge negatively impacts the electric machine operating area. Additionally, as it will be demonstrated in this work, reducing the DC-Link voltage lowers inverter power losses. In operating points where the necessary machine voltage is lower than the battery voltage rated value, a fixed DC-Link voltage equal to the battery voltage results in additional inverter losses. The focus of this work is on the design and analysis of a battery electric vehicle drivetrain using an additional DC-DC converter extension in it. Accordingly, the main objective is to investigate the energy efficiency benefits of shifting the operating points of the drivetrain components by placing a DC-DC converter between the battery and the inverter-fed machine. For this purpose, a multiphase interleaving converter is selected, and through comprehensive modeling of the drivetrain, the appropriate control system is designed and evaluated on the one hand, and loss optimizing operating strategies are developed on the other hand to take the most advantage of the integration of a DC-DC converter into the drivetrain

Magnetic Material Modelling of Electrical Machines

The need for electromechanical energy conversion that takes place in electric motors, generators, and actuators is an important aspect associated with current development. The efficiency and effectiveness of the conversion process depends on both the design of the devices and the materials used in those devices. In this context, this book addresses important aspects of electrical machines, namely their materials, design, and optimization. It is essential for the design process of electrical machines to be carried out through extensive numerical field computations. Thus, the reprint also focuses on the accuracy of these computations, as well as the quality of the material models that are adopted. Another aspect of interest is the modeling of properties such as hysteresis, alternating and rotating losses and demagnetization. In addition, the characterization of materials and their dependence on mechanical quantities such as stresses and temperature are also considered. The reprint also addresses another aspect that needs to be considered for the development of the optimal global system in some applications, which is the case of drives that are associated with electrical machines

Sustainable Development (SD) Design of an Electrical System A Case Study of Asiaflex Products Sdn B lid

Sustainable development (SD) is a simple way of ensuring a better quality of life for everyone, now and for generation to conic. It refers to a perspective that considers all three aspects which are social, economic and the environmental. Designing an electrical system with sustainability refers to an approach that considers the use of renewable energy, energy efficiency, conservation and nlnmising usage of natural resources

Modelling and control techniques for multiphase electric drives: a phase variable approach

Multiphase electric drives are today one of the most relevant research topics for the electrical engineering scientific community, thanks to the many advantages they offer over standard three-phase solutions (e.g., power segmentation, fault-tolerance, optimized performances, torque/power sharing strategies, etc...). They are considered promising solutions in many application areas, like industry, traction and renewable energy integration, and especially in presence of high-power or high-reliability requirements. However, contrarily to the three-phase counterparts, multiphase drives can assume a wider variety of different configurations, concerning both the electrical machine (e.g., symmetrical/asymmetrical windings disposition, concentrated/distributed windings, etc...) and the overall drive topology (e.g., single-star configuration, multiple-star configuration, open-end windings, etc…). This aspect, together with the higher number of variables of the system, can make their analysis and control more challenging, especially when dealing with reconfigurable systems (e.g., in post-fault scenarios). This Ph.D. thesis is focused on the mathematical modelling and on the control of multiphase electric drives. The aim of this research is to develop a generalized model-based approach that can be used in multiple configurations and scenarios, requiring minimal reconfigurations to deal with different machine designs and/or different converter topologies, and suitable both in healthy and in faulty operating conditions. Standard field-oriented approaches for the analysis and control of multiphase drives, directly derived as extensions of the three-phase equivalents, despite being relatively easy and convenient solutions to deal with symmetrical machines, may suffer some hurdles when applied to some asymmetrical configurations, including post-fault layouts. To address these issues, a different approach, completely derived in the phase variable domain, is here developed. The method does not require any vector space decomposition or rotational transformation but instead explicitly considers the mathematical properties of the multiphase machine and the effects of the drive topology (which typically introduces some constraints on the system variables). In this thesis work, the proposed approach is particularized for multiphase permanent magnet synchronous machines and for multiphase synchronous reluctance machines. All the results are obtained through rigorous mathematical derivations, and are supported and validated by both numerical analysis and experimental tests. As proven considering many different configurations and scenarios, the main benefits of the proposed methodology are its generality and flexibility, which make it a viable alternative to standard modelling and control algorithms